1. Field of the Invention
The present invention relates to a rotor for a synchronous reluctance motor and a manufacturing method thereof, and particularly, to a rotor for a synchronous reluctance motor of flux barrier type and a manufacturing method.
2. Description of the Background Art
A synchronous reluctance motor is a kind of synchronous motor, and it has relatively low price, and high efficiency and responsiveness, however, it has a complex structure and it is hard to be manufactured, whereby it takes a lot of costs and times. Therefore, it is not mass-produced nowadays.
The synchronous reluctance motor as described above comprises a stator and a rotor formed by insulatingly stacking a plurality of steel plates. Herein, the stator is nearly similar to a general stator in an induction motor, and the rotor includes a rotor core on which a plurality of flux barriers are formed in order to generate difference between a magnetic resistance.
FIG. 1 is a view showing a rotor core in the synchronous reluctance motor of flux barrier type according to the conventional art.
As shown therein, the conventional rotor core is made by a plurality of magnetic core steel plates 111 formed as circular plates, which are stacked along with a rotation shaft line direction so as to be insulated with each other, and a shaft hole 112 is formed at a center part of the respective core steel plates 111 so as to receive a rotational shaft. A plurality of bolt holes 113 are formed on boundary part of the shaft hole 112 so as to receive a fixing bolt (not shown) which couples and fixes the stacked respective core steel plates 111 integrally in the shaft line direction.
On the other hand, a plurality of magnetic pole portions P1xcx9cP4 are formed on boundary part of the respective core steel plates 111, and a plurality of flux barrier groups B1xcx9cB4 are formed between the respective magnetic pole portions P1xcx9cP4 so as to generate a difference between the magnetic resistance.
The respective flux barrier group B1xcx9cB4 includes a plurality of flux barriers 115 which are formed as penetrating the plate surface so that both ends are abutting on a circumference and a center part has an arc shape protruded toward the shaft hole 112, and disposed alternatively with magnetic paths 117 in radial direction of the core steel plates 111. A plurality of lugs 119, which are depressed from one plate surface and protruded toward the other plate surface, and therefore inserted into the depressed parts of the another lug 119 when the plates are stacked, are formed on the magnetic paths 117 between the respective flux barriers 115.
However, according to the rotor of the conventional flux barrier type synchronous reluctance motor, many flux barriers 115 and lugs 119 are formed on the core steel plate 111, and therefore, a strength of the motor is weak so that a distortion may be generated, a phenomenon that the core steel plates 111 are separated from each other at their edges may be generated, and it took much time and cost to assemble so that the manufacturing cost is increased.
Especially, the flux barrier type synchronous reluctance motor is now experimentally manufactured, and can not be mass-produced and utilized.
Also, the rotor of the conventional synchronous reluctance motor can not be applied to a skew type rotor in which the flux barrier is disposed to have a predetermined skew for the rotational shaft due to arranging structure of the lugs 119 and shapes of the flux barriers 115.
On the other hand, FIG. 2 is a view showing an another example of the rotor core in the conventional flux barrier type synchronous reluctance motor. As shown therein, a rotor core 120 is made by stacking a plurality of circular plate members 121 including a plurality of holes 122 of arc shapes formed on boundary.
The respective circular plate member 121 is made using one of a magnetic member or non-magnetic member. In case that the circular plate member is made using the magnetic member, the flux barrier is formed by filling a nonmagnetic filling member 123 into the hole 122 of arc shape after stacking the plates. In addition, in case that the circular plate member is made using the nonmagnetic member, a magnetic filling member 123 is filled in the hole 122 after stacking the plates to form a magnetic pole part, whereby the rotation power is generated by the difference of the magnetic resistance.
However, according to the rotor of the conventional flux barrier type synchronous reluctance motor described above, the circular plate members 121 is stacked, after that, the filling member 123 is filled into the holes 122, and a boundary part 124 is removed by machining after the filling is completed. Therefore, an additional filling device for filling the filling member 123 and an additional device for fabricating the boundary part, and also, it takes much time to manufacture the product and the manufacturing cost is increased.
Also, the rotor of the conventional flux barrier type synchronous reluctance motor is difficult to be applied to the rotor of skew type due to the structure of the hole 122 which is formed as an arc.
Therefore, an object of the present invention is to provide a rotor for a synchronous reluctance motor and a manufacturing method which can be easily manufactured, is able to reduce manufacturing cost, and suitable for mass producing by automatically stacking core steel plates regardless of skew type or non skew type.
To achieve the object of the present invention, as embodied and broadly described herein, there is provided a rotor for a synchronous reluctance motor according to the present invention comprising: a plate stacked body made by stacking a plurality of magnetic core steel plates on which a shaft hole is formed at center part and a plurality of flux barrier groups are formed around the shaft hole; end plates which are disposed on both sides of the plate stacked body; a coupling means penetrating the flux barrier groups and coupling the plate stacked body and the end plates as a single body; and a rotational shaft which is inserted into the plate stacked body and the end plates.
The flux barrier group includes a plurality of flux barriers having both end parts abutting on an outer circumference of the core steel plate and a center part of arc shape hole protruded toward the shaft hole.
The flux barriers are formed so that widths of the holes are gradually increased from the outer circumference to the shaft hole along with the radial direction of the core steel plate, and the widths of the holes are gradually reduced toward both ends. In addition, the respective flux barrier includes a straight line part at their center part.
Four flux barrier groups are formed so as to be symmetric with each other, and the respective flux barrier group includes three flux barriers.
The coupling means passes through a flux barrier which is located in the middle of the three flux barriers.
In addition, the coupling means includes a rivet which passes through at least one flux barrier among those the plurality of flux barriers in the plate stacked body from the end plate on one side and is exposed as passing through the end plate on the other side.
Herein, the coupling means may include a fixing bolt which penetrates at least one flux barrier among those plurality of flux barriers in the plate stacked body from the end plate on one side and is exposed to the end plate on the other side, and a nut which is coupled to the exposed end of the fixing bolt using a screw.
An automatic stacking point which is coupled to the other when the plates are stacked is formed on the core steel plate, and the automatic stacking point is protruded from one surface of the core steel plate to the other surface. The automatic stacking point is protruded as a square shape.
The automatic stacking point may be formed on boundary part of the shaft hole, or may be formed on an outer circumference of the core steel plate between the flux barriers.
On the other hand, a plurality of pin holes are formed on the boundary part of the shaft hole on the core steel plate, and a pin can be inserted into the pin hole to be fixed.
A manufacturing method of the rotor for the synchronous reluctance motor according to the present invention comprises: a step of forming a core steel plate of magnetic disc on which a shaft hole is formed at center, a plurality of flux barrier groups are formed centering around the shaft hole, and automatic stacking points are formed; a step of forming a plate stacked body by continuously stacking the core steel plates using the automatic stacking points; a step of disposing the end plates on both sides of the plate stacked body; and a step of coupling the end plates and the plate stacked body integrally by passing through the flux barriers.
The step of forming the plate stacked body comprises: a step of forming the automatic stacking points between the flux barriers adjacent to the shaft hole; and a step of rotating at least one steel plate between the steel plate which will be stacked after forming of the automatic stacking point and the steel plate which was stacked before as a predetermined angle.
The step of coupling the end plates and the plate stacked body integrally with each other is made by riveting as penetrating one of the plurality of flux barriers on the plate stacked body from the end plate on one side.
Also, there is provided a manufacturing method of the rotor for the synchronous reluctance motor according to the present invention comprising: a step of forming a magnetic core steel plate of disc form, on which a shaft hole is formed at center part and a plurality of pin holes are formed an boundary part of the shaft hole and a plurality of flux barrier groups which are symmetrically formed to each other; a step of manufacturing the plate stacked body by continuously stacking the core steel plates; a step of coupling a pin into the pin holes of the plate stacked body; a step of disposing nonmagnetic end plates of disc shape on both sides of the plate stacked body; and a step of fixing the end plates and the plate stacked body as a single body by penetrating one of the plurality of flux barriers using a coupling member made by nonmagnetic material.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.